Two of the three energy efficiency solutions used on Meridian's Kurow farm were found during visits to the New Zealand Agricultural Fieldays at Mystery Creek.

One of the solutions is a computer device, Varivac, which provides accurate control of the electrical pump that drives the milk shed vacuum pump. The device enables the pump to work only as hard as it needs to to provide the required vacuum, which varies as cows are put on and off the system. The pump used to run continuously at 15kW. Now it runs at an average of 4.5kW. By requiring less power and running only as needed, it is expected the pump unit will last longer and require less maintenance. The noise level in the shed has also been reduced.

Milk quality has also improved.

The constant pressure of the system has reduced the incidence of mastitis.

The second innovation is Mahana Blue, a system that takes waste heat from the milk and uses it to heat water to 85degC, which is then used to clean the equipment and shed.

Meridian rural and business segment manager Nigel Broomhall described Mahana Blue as a "brilliant device." The Kurow dairy had two hot-water heaters drawing 12kW of power. The new device has seen usage drop to 3kW.

The third innovation is the installation of a grounded copper ring around the milking shed's rotary bale. This has eliminated stray voltage, which was high enough for some cows to detect.

"Not only has energy consumption at the farm been cut by nearly 30 percent, the quality of milk has improved and the time taken to milk the cows has been halved," Mr Broomhall said.

The technologies had the potential to reduce energy usage at dairy farms throughout New Zealand.